1. Field of the Invention
This invention relates generally to video tape playback systems in which a number of tapes are transported from a magazine to various video tape playback machines and, more particularly, to apparatus adapted to select a desired tape cassette from a large number of such cassettes housed in a housing block, to provide such selected cassette to a video tape recorder, and to return a cassette back to the housing block.
2. Description of the Background
There are now known automatic cassette loading systems for providing a selection from a large number of tape cassettes to a video tape recorder (VTR) based upon a predetermined program. That is, a computer-type controller is provided with a sequence of desired tapes and then this controller operates to control the automatic cassette loading apparatus to provide sequential video reproduction of the information on the various cassette tapes. This system is typically employed in television broadcast stations to playback commercials and the like in a desired sequence. Although these systems are generally provided to playback the material on the various cassettes such systems may also be employed to record information, that is, the video tape recorder is operated in the recording mode.
Typically the automatic tape transferring systems have large magazines or housing blocks that contain a large number of video cassettes and employ a delivery mechanism that is movable relative to the housing blocks and which can select a video cassette and transport it to the video tape recorder for playback. The typical automatic system such as described above includes a number of video tape recorders in order to permit the sequential operation of the program material with no interruptions between the program segments.
In the typical broadcast station, the programs to be broadcast for each day are sequentially broadcast using a system as described, however, generally during the broadcast of the programs it is desired to insert the prerecorded commercial messages. Because there are a large number of different commercials each day, it is necessary to provide as many as several thousand individual cassettes, thus, the requirement for high-speed action of the cassette transfer system is important.
One system known heretofore has a cassette transferring device that deals with separate arrays or magazines of cassettes, which are arranged in side-by-side relationship with the tape transferring device operating between the two arrays of cassettes. Generally, the tape transfer device has two mechanisms each of which operates in the opposite direction but can only operate in its dedicated direction. Thus, in the typical operation, a desired tape is moved into the transferring device using the appropriate direction drive element, is transported to the video tape recorder for playback, and then using the other of the two directional drive elements is picked up from the video tape recorder after playback, thereby permitting it to be reinserted back into its home slot. This presents a problem, however, when it is desired to rearrange these cassettes in the housing such that it is necessary to remove a tape from the housing using the transferring device that operates in one direction, place it in the other, opposite housing, and then utilize the other element in the transferring device to select it and reposition it back into the original housing at another location. This, of course, becomes very time consuming when there are a large number of tape cassettes to be rearranged. Not only does the procedure become time consuming, but the system needed to control the tape transfer device becomes quite complex.
Therefore, in utilizing the known equipment when decisions are being made concerning the reproducing order of the cassettes and their housed positions, the controller program must be arranged with a close watch on the frequency of use of the cassettes as well as their reproducing times. In addition, the path for transferring the cassette within each block must be controlled to cut down on transfer time.